1. Field of the Invention
This invention relates in general to exercise machines and in particular to machines for exercising abdominal muscles.
2. Description of Prior Art
Many machines have been proposed, some of which have been commercially produced, for allowing a person to exercise abdominal muscles. Examples of such machines are disclosed in U.S. Pat. Nos. 4,627,619, 4,623,144, 4,600,196 and 4,387,893. The machines of these patents allow a user to sit in the machine and bend forward at the waist, rather than the hip, so as to properly exercise the user's abdominal muscles. Such machines are all characterized by a fixed support member and a rotating member, with the rotating member having opposite pivot points on the support member which roughly align with the sternum or breastbone of the user. Such placement of the rotating members with respect to the stationary support member allows the user to push against the rotating member resulting in a circular arc about a line through the pivot points and the user's waist.
Other machines for exercising abdominal muscles while also exercising lower back muscles provide mechanisms which allow the user to bend backward from a seated position. The machine disclosed in U.S. Pat. No. 4,666,152 is an example of such a machine. Such machine includes back and lap supports with a mechanism which resists backward rotation by the user.
All of the machines of the type described above include structure tall enough to provide pivot points to align with the user's sternum. Consequently such machines include high supporting structure on both sides of the user which makes entry and exit to and from the machine cumbersome.